Long-term climate dynamics in the extra-tropics of the South Pacific revealed from sedimentary charcoal analysis

We synthesized 13 high-resolution charcoal records located within the current zone of strongest correlation between the southern westerly winds (SWW) and rainfall on Earth in an attempt to assess how shifts in the SWW drive climatic change in this region. High regional charcoal influx values are found during the early Holocene (12-8 ka), progressively decreasing and reaching a minimum during the mid-Holocene (∼5 ka). Wavelet coherence analysis between regional charcoal influxes from southern South America (SSA) and western Tasmania (WTAS) shows a tight periodicity coherence from 12 to ∼6 ka, supporting synchronous SWW-driven climatic change in these areas. The same analysis between the regional Tasmania charcoal influx and an ENSO proxy suggests a coherent pattern of frequency variability between these records since ∼6 ka, highlighting the importance of ENSO in altering fire regimes in this region. Our data also provides insights into the non-stationarity of the climate system in space and time and highlights the potential limitations of modern climatic relationships for informing our understanding of the global climate system.